What was found
(CAN) THIS IS AN ON GOING ISSUE. THIS EXHAUST MUFFLER PASSED THE VISUAL INSP AS CF90-03. WHEN PRESSURE TESTED WITH AIR AND WATER, 3 PIN HOLES SHOWED. 2 WERE IN OPEN BARE METAL SURFACE. ONE WAS IN THE LONGITUDINAL SEAM. ANOTHER EXPERIENCED AME WAS IN MY SHOP FOR OTHER REASONS. ASKED HIM TO VISUALLY INSPECT IAW CF90-03. EVEN THOUGH HE KNEW THERE WERE LEAKS, SO HE LOOKED MORE INTENSELY, HE WAS UNABLE TO FIND ANY, VISUALLY. THIS IS A 50 PERCENT FAILURE RATE FOR ACFT IN MY SHOP. AGAIN, THIS SHOP ONLY DOES BUBBLE TESTS AS THE VISUAL TEST, IAW CF90-03.